What is alpha beta ratio in radiobiology?
The ratio of the two parameters, α/β, is a measure of the fractionation sensitivity of the cells: cells with a higher α/β, are less sensitive to the sparing effect of fractionation.
What does a low alpha beta ratio mean?
Generally speaking, the higher the alpha/beta ratio is, the more linear the cell survival curve is. Whereas the lower the alpha/beta ratio is (high beta relative to alpha), the more curved the cell survival curve is.
Is malignant melanoma radiosensitive?
Locally advanced melanoma is clinically challenging; melanomas are considered radioresistant (Harwood & Cummings, 1981). Recent reports, however, show variable radiosensitivity in patients and established cell lines (Stevens & McKay, 2006) (Sambade et al, 2011).
Is radiotherapy effective for melanoma?
Radiation can be used to treat melanoma that has come back after surgery, either in the skin or lymph nodes, or to help treat distant spread of the disease. Radiation therapy is often used to relieve symptoms caused by the spread of the melanoma, especially to the brain or bones.
What is the value of Alpha Beta?
Both alpha and beta are historical measures of past performances. Alpha shows how well (or badly) a stock has performed in comparison to a benchmark index. Beta indicates how volatile a stock’s price has been in comparison to the market as a whole. A high alpha is always good.
What is the alpha beta ratio for spinal cord?
The study suggests that the spinal cord has a similar α/β ratio for patients, rats and other large animals, such as dogs, monkeys, and pigs. The α/β ratio is close to 3.9 Gy, with a 95 % CI of (3.0, 4.9) for the combined group, and (2.2, 8.2) for the patient only group.
What is desmoplastic melanoma?
Desmoplastic melanoma is a type of skin cancer. It begins when the melanocytes in the skin grow out of control and form tumors. Melanocytes are the cells responsible for making melanin, the pigment that determines the color of the skin.
Does melanoma respond chemo?
Chemotherapy doesn’t work as well against melanoma as it does for some other types of cancer. Doctors are more likely to use newer drugs called targeted cancer drugs or immunotherapy first to treat melanoma.
How do you beat stage 4 melanoma?
But if you have stage 4 melanoma, your doctor might recommend radiation therapy to treat tumors that have spread to other organs. In some cases, your doctor may recommend radiation therapy before surgery. This may help shrink melanoma tumors and make them easier to remove.
How long is radiation therapy for melanoma?
Patients undergoing radiation for treatments to individual symptomatic lesions may have a course of treatment that ranges from a single session to daily treatment sessions for two to three weeks. Side effects depend on where the melanoma is located but typically include fatigue and skin irritation.
How do you calculate alpha beta?
Alpha = R – Rf – beta (Rm-Rf) R represents the portfolio return. Rf represents the risk-free rate of return. Beta represents the systematic risk of a portfolio. Rm represents the market return, per a benchmark.
How big is subungual melanoma under the nail?
Subungual melanomas usually appear as a brown or black streak under the nail. 3,4 Typically, these streaks gradually increase in size and are usually larger than 3mm. 1 Unlike nail infection or trauma to the nails, subungual melanoma typically affects one nail at a time. 3,4
How is melanoma diagnosed in the toenails?
Diagnosing and treating subungual melanoma is much more involved. Once your doctor performs the initial assessment and determines you might have subungual melanoma, they’ll commonly suggest a nail biopsy. A nail biopsy is the primary diagnostic tool available for making a definitive diagnosis.
Where does advanced stage melanoma of nail unit go?
Advanced stage Melanoma of Nail Unit can invade into the tissue and bone beneath the nail. It can also metastasize beyond the nail and skin, to the lymph nodes and other organs. Organs that are commonly involved in metastasis include: Lung. Liver. Brain. Bone. Gastrointestinal tract.
What kind of skin cancer is under my toenails?
Toenail melanoma is another name for subungual melanoma. It’s an uncommon form of skin cancer that develops underneath the fingernail or toenail. Subungual means “under the nail.” Toenail fungus is a more common condition that occurs from the overgrowth of fungi in, under, or on the nail.